tsuru exports an special environment variable in applications that use
services, this variable is named TSURU_SERVICES.
The value of this example is a JSON describing all services instances that the
application uses. Here is an example of the value of this variable:

As described in the structure, the value of the environment variable is a JSON
object, where each key represents a service. In the example above, there are
three services: mysql, redis and mongodb. Each service contains a list of
service instances, and each instance have a name and a map of environment
variables.